Gram quantity separation of polar compounds (trp-leu and val-tyr) was achieved with a hydrophilic solvent system composed of n-butanol acetic acid/water (4:1:5) by the use of a large diameter coiled column (0.55 cm i.d.) on a horizontal flow-through coil planet centrifuge described in the previous report. Using a short coiled column, stationary phase retention and peak resolution were studied under various operational conditions by altering helical diameter, rpm, flow rates, and elution mode of the mobile phase. Under the optimum operational conditions (300 rpm and 120 ml/h flow rate) preparative-scale separations were performed on 1g quantity of samples with a long column (30 m in length, 750 ml capacity and 7.5 cm helical diameter). The sample-loading capacity of the present system may be further increased by the use of longer and/or larger-diameter columns.